Mechanism for synchronizing and controlling multiple actuators of a slide out room of mobile living quarters

ABSTRACT

A slide out room is a extended from a mobile living quarters to provide auxiliary space and is retracted into the mobile living quarters when the unit is to be moved by a pair of independent actuators. A control is provided which responds to signals generated by position sensors for each actuator to interpret a corresponding actuator whenever the position of one of the actuators exceeds the position of the other actuator by more then a predetermined offset. The actuators are stopped whenever they attain a corresponding “room in” or a “room out” stop limit. The stop limits are set by independently advancing the actuators after they have attained default limit to set the out and in stop limits independently between the actuators. The offset can be set as the difference between the “in” stop limits of the actuators, or can be set by advancing the slide out room away from the fully retracted position a small distance, then independently controlling the actuators until the slide out room achieves a desired orientation with the respect to the main living quarters, and then setting the offset as equal to the difference of the readings of the position sensors when the slide out room is in the desired orientation.

BACKGROUND OF THE INVENTION

[0001] This is a continuation-in-part of U.S. patent application Ser.No. 09/220,165, filed Dec. 23, 1998.

FIELD OF THE INVENTION

[0002] This invention relates to a mechanism for controlling theactuation of a slide out room used on mobile living quarters (such as arecreational vehicle).

DISCUSSION OF THE PRIOR ART

[0003] The width of mobile living quarters, such as recreationalvehicles, is limited to that which may be accommodated for travel on thepublic highways. Accordingly, when the mobile living quarters is parkedfor use, it is desirable to be able to expand the living quarters, toincrease the available living area. So called slide out rooms havebecome popular to effect expansion of the available living area of suchmobile living quarters. These slide out rooms are retracted into themain living area when the mobile living quarters are transported on thepublic highways, and then are extended from the main living quarters toprovide additional living space when the mobile living quarters isparked for use. Slide out rooms are typically mounted on telescopingtubes which are mounted on the frame supporting the main living area andare actuated by hydraulic rams, electric motors, or similar actuationdevices. Typically, two or more such actuation devices are required.Slide out rooms are only semi-rigid. Furthermore, the two or moreactuators are often not symmetrically located with respect to the slideout room, because placement of the actuators must accommodate wheelwells and other structural components of the mobile living quarters. Itis necessary to synchronize operation of the actuators, and it isdesirable to be able to control the “room out” and “room in” positionsfor the actuators to assure that the room is fully extended across itsentire length when the room is extended for use, and to assure that itis fully retracted across its entire length when the room is retractedto permit the mobile living quarters to be moved. Failure to fullyextend or fully retract the slide out room across its entire lengthpermits gaps to occur between the seals that seal the slide out room tothe main living quarters, thus permitting moisture to leak into theunit. Failure to synchronize properly the motion of the actuators maycause undesirable deflection across the length of the room, againresulting in damage, seal problems, and unsightly appearance of theroom.

SUMMARY OF THE INVENTION

[0004] According to the present invention a pair of electric motoractuators drive an acme threaded jack screw, or a rack and pinion drive,etc. connected to the slide out room to effect extension and retractionof the slide out room relative to the main living quarters. Although theinvention is described in connection with a pair of electric motoractuators, it is apparent to those skilled in the art that the inventionis equally applicable to systems having three or more electric motoractuators. Larger slide out rooms may require more than two electricmotor actuators to effect extension and retraction of the slide outroom. According to the invention, a position sensor, which may be aresistive strip secured to the actuators, or a rotary potentiometerturned by momentum of the actuators, provides a signal representative ofthe absolute position of the room. Optionally, a pulse generatingencoder generates pulses in response to the operation of the actuatorsto provide an indication of movement of the actuators relative to oneanother. The pulses are counted to indicate the relative position ofeach actuator. Stop limits may be established as hereinafter provided tocontrol the “in” and “out” positions of the slide out room.

[0005] According to another feature of the invention, operation of theactuators is synchronized so that the back wall of the slide out roomremains substantially parallel to the wall of the mobile living quartersfor most of the outward and inward travel of the slide out room.Optionally, when the slide out room reaches a point within, for example,five percent of the inner and outer stop limits, synchronization isremoved, and each of the actuators travel independently of the other tothe “out” or “in” stops. Each “out” stop limit and each “in” stop limitis set independently to assure that full contact with the necessaryseals is made when the room is extended into its full extended positionor retracted into the fully retracted position. An optionalinitialization procedure is provided to permit the stops to be setindividually, so that the stops may be set for each unit, since thedeflection of the slide out room and positioning of the seals will varyslightly from unit to unit. According to another feature of theinvention, the offset between the actuators, which is maintained bysynchronization during extension and retraction of the slide out room,is set independently of the stops, thereby enabling the stops to be setto effect proper sealing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] These and other advantages of the present invention will becomeapparent from the following description, with reference to theaccompanying drawings, in which:

[0007]FIG. 1 is a view in perspective of mobile living quartersincorporating a slide out room made pursuant to the teachings of thepresent invention;

[0008]FIG. 2 is a view in perspective of the mobile living quartersillustrated in FIG. 1, but taken from below to illustrate the manner inwhich the slide out room is supported for movement on the main livingquarters and also to illustrate portions of the actuation mechanism;

[0009]FIG. 3 is a schematic illustration of the actuation and controlsystem used to operate the slide out room illustrated in the preferredembodiment of the invention;

[0010]FIG. 4 shows a flow chart of the controller process controllingthe slide out room in accordance with the embodiment of FIG. 3;

[0011]FIG. 5 is a schematic view similar to that of FIG. 3 showing analternate actuation system;

[0012]FIG. 6 shows the flow chart of the controller process controllingthe slide out room in accordance with the embodiment of FIG. 5;

[0013]FIG. 7 shows the flow chart of an alternate controller process foruse with FIG. 5;

[0014]FIG. 8 shows a flow chart of the termination sub routines for usewith FIG. 7;

[0015] FIGS. 9-11 shows a flow chart of alternate termination subroutines for use with FIG. 7;

[0016]FIG. 12 shows a diagrammatical view similar to that of FIG. 3having a clutch installed intermediate the motor and gear box of theslave motor;

[0017]FIG. 13 shows a flow chart of the operation control for use withthe embodiment of FIG. 12;

[0018]FIG. 14 shows a schematic view of an embodiment similar to that ofFIG. 5 having clutches installed intermediate its motors and gear boxes;

[0019]FIG. 15 shows a flow chart of a control mechanism for use with theembodiment of FIG. 14;

[0020]FIG. 16 shows a schematic view of an embodiment similar to that ofFIG. 3 having a clutch installed intermediate one of its motors and gearboxes;

[0021]FIG. 17 shows a flow chart of a control mechanism for use with theembodiment of FIG. 16;

[0022]FIG. 18 shows a schematic view of an embodiment similar to that ofFIG. 5 having clutches installed intermediate both of its motors andgear boxes;

[0023]FIG. 19 shows a flow chart of a control mechanism for use with theembodiment of FIG. 18;

[0024]FIG. 20 shows the flow chart of an optional initialization subroutine; and

[0025]FIG. 21 shows a flow chart of the method of setting the off set.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0026] Referring now to FIGS. 1 and 2, mobile living quarters, such as arecreational vehicle, is generally indicated by the numeral 10 andincludes side walls 12, 14, end walls 16, 18, and a floor 20 (FIG. 2)which is supported on a frame consisting of a pair of longitudinallyextending main frame members 22, 24. Axles 26 are mounted on the framemembers 22, 24 via conventional suspension apparatus (not shown) andsupport wheels 28 to thereby permit movement of the mobile livingquarters 10.

[0027] Wall 12 of mobile living quarters 10 includes a large aperture 30which slidably receives a slide out room generally indicated by thenumeral 32, which is slidably mounted for movement relative to the wall12 from an extended position illustrated in FIGS. 1 and 2 of thedrawings, in which the slide out room 32 is extended to provideauxiliary living space, to a retracted position retracted within mobileliving quarters 10 to permit the mobile living quarters 10 to be movedon public roads. The slide out room 32 includes an back wall 34 which,when the slide out room is retracted within the main living quarters, issubstantially flush with the wall 12. Slide out room 32 also includesside walls 36, 38, ceiling 40, and floor 42, it being noted that thelower portion of the back wall 34 extends below the bottom side of thefloor 42.

[0028] The slide out room 32 is guided for movement between the extendedand retracted positions by a pair of extensible tubular members 44, 46.Each of the members 44, 46 include an outer tubular member 48, 50 whichare secured to the frame members 22, 24 and extend through openingsformed therein. The outer tubular members slidably receive a.corresponding inner tubular member 52, 54, each of which is secured tothe portion of the outer wall 32 extending beneath the lower surface ofthe floor 42 as described above. The slide out room 32 is moved betweenthe extended and retracted positions by electric motor drives includinga pair of electric motors 56, 58. Optionally, hydraulic actuators wellknown in the art may be used instead of the electric motors 56, 58, thehydraulic actuators being controlled by opening and closing valvescontrolling communication of hydraulic fluid to the actuators. While thespecific embodiment is shown below the floor, it should be appreciatedthat this invention is also usable either in the floor or above thefloor.

[0029] With respect now to FIG. 3, the first embodiment of the controlmechanism will be shown which is designed as, and will be referred toas, a master/slave version having two actuator motors 56 and 58 eachbeing controlled by a sensor/encoder 68, 70. Motors 56, 58 arereversible motors and turn acme-threaded jack screws 60, 62 throughtheir corresponding gear boxes 64, 66. The jack screws 60, 62 are notillustrated in FIG. 2 but preferably extend through inner tubularmembers 52 and 54 to provide actuation of the slide out room 32. Itshould be appreciated that the jack screws 60, 62 mesh with fixedthreaded members attached to the slide out room 32, whereby rotation ofthe jack screw moves the slide out room in and out. Alternatively, arack-and-pinion drive may be used.

[0030] With respect still to FIG. 3, each of the gear boxes 64, 66 isequipped with sensors 68-70 which generate signals representing theabsolute position of the jack screws 60, 62. The sensors 68-70 may belinear encoders comprising a resistive strip that provides increased (ordecreased) resistance depending on the distance that the slide out room32 extends. Alternatively, rotary potentiometers turned by the jackscrews, or rotary potentiometers turned by a cable attached to innertubular members 52, 54, or a rack and pinion system connected to thefloor and then connected to a potentiometer, may be used. Accordingly, asignal representing the absolute position of the actuator with respectto the fully retracted position is provided. Optionally, the sensors 68,70 may be rotary type encoders that generate pulses proportional to theturning of the jack screw 60 or 62, or rotary encoders turned by a cableattached to inner tubular member 52, 54 or linear encoders that generatepulses responsive to extension and retraction of the actuators, or arack and pinion system connected to the floor and then connected to anencoder, may be used. The pulses are counted to generate a signalindicative of the relative position of the jack screws 60, 62. Bothtypes of encoders or sensors are well known to those skilled in the art.The output of the sensors/encoders are fed to a controller generallyindicated by the numeral 72, which also controls the motors 56, 58.

[0031] The controller 72 includes an output terminal 74 connected toright hand motor 56, an output terminal 76 connected to left hand motor58, and terminals 78, 80, which receive signals from thesensors/encoders 68, 70, respectively. This embodiment will be referredto as a Master/Slave version, as this embodiment has master stopswitches, referred to diagrammatically in FIG. 3 as 81 a, 81 b, whereasthe opposite motor has no such stop switch, but rather is a slave to themaster. FIG. 3 shows the stop switches as an IN stop switch at 81 a, andan OUT stop switch at 81 b. While the switches are showndiagrammatically as physically located adjacent to the jack screw 62, itshould be appreciated that the switches could be located anywhere, orcould be located within the control mechanism 72, receiving a physicallocation signal from the encoders 68, 70. Alternatively, they could bemechanical limit switches, receiving their input from the movement ofthe room 32 and or from the screw 62, with output to the controlmechanism 72. Furthermore, they could be over current switches whichstop the motors upon an over current draw. In any event, the IN stopswitch and OUT stop switch cooperate with the embodiment to stop themotors, or otherwise the movement of the room, to prevent further inwardor outward movement.

[0032] A main control switch generally indicated by the numeral 82 is athree-position switch, with a pair of output terminals, one of which isconnected to “IN” terminal 84 of controller 72 and the other beingconnected to the “OUT” terminal 86. When the switch arm 88 is moved toengage the “IN” terminal 84, the motors 56, 58 are actuated as will behereinafter explained to retract the slide out room into the mobileliving quarters. When the switch arm 88 is moved into engagement withterminal 86, the motors 56, 58 are energized in a direction extendingthe slide out room from the mobile living quarters. When the switch arm88 is in the neutral position illustrated, both of the motors 56, 58 areturned off.

[0033] The switch 82 is preferably a momentary contact switch in whichthe user must maintain the switch arm in engagement with thecorresponding terminals. When the switch arm 88 is released, the switcharm 88 immediately returns to the off position illustrated.Alternatively, the switch 82 may be a maintained contact switch, suchthat when the switch arm 88 is engaged with either of the terminals 84or 86 the slide out room extends or retracts until the aforementionedstops are engaged. Preferably, the switch 82 is mounted on the wall ofthe mobile living quarters adjacent the slide out room and includes aswitch plate covered by a switch cover (not shown). Concealed beneaththe switch cover (not shown), or in any other appropriate place wherethey are concealed from the owner during normal use but are readilyaccessible to a serviceman, are a right motor override switch generallyindicated by the numeral 90 and a left motor override switch generallyindicated by the numeral 92. When the switch 90 is operated and theswitch 82 is moved to either the IN or the OUT position, the right motor56, but only the right motor 56, is toggled, in either the IN or the OUTdirection, depending upon the position of the switch arm 88. Similarly,the left motor override switch 92 toggles the left motor 58 in eitherthe IN or the OUT direction, again depending upon the position of theswitch arm 88. Accordingly, to toggle either of the motors 56 or 58individually, the serviceman must operate both the switches 88 and 90 or88 and 92 at the same time. Also similarly concealed beneath the switchcover is a momentary contact set switch generally indicated by thenumeral 94. The set switch 94 is operated to set limits and for otherpurposes as will be described in detail hereinafter.

[0034] Referring now to FIGS. 3 and 4, operation of the controls for themotors 56, 58 will be explained. The main control is illustrated in FIG.4, which responds to operation of the switch 82 to read the switchinputs as indicated at 96. If the set switch 94 (FIG. 3) is pushed, aninitialization subroutine is called, as indicated at 98. Theinitialization subroutine will be explained in detail hereinafter.

[0035] Various embodiments of the synchronization concept will bedescribed herein. It should be appreciated that the move-out room hasfully retracted positions and fully extended positions. These are theextreme positions which are intended to be where the user will place theroom, and where the room is in its optimum position, in or out forsealing purposes, and/or alignment. These positions will be referred toas IN limit position or OUT limit position. Other embodiments will bedescribed where the room is intended to move to positions “shy” of theIN limit position or OUT limit position, and be halted there. These shypositions will be referred to as “IN reference positions” and “OUTreference positions”.

[0036] After started by operation of switch 82, the program thenproceeds to test at 100 to determine if the switch 82 is in the “out” or“in” position. If the switch arm 88 has been moved into contact terminal86, the room is to be moved to the extended position. As indicated at102, the sensors 68 and 70 are read, the out limit as measured by switch81 b, which is either set in memory when the unit is manufactured or isset by the initialization subroutine as will hereinafter be explained,is read, and an initial offset between the sensors is read. The sensorsmay not have the same “zero” datum, so that the synchronization of theactuators must take into account the initial offset. Similarly, if thepulse type encoders are used, the initial pulse readings may be verydifferent, so that this initial offset is either set when the unit isassembled or is set by the initialization subroutine. As indicated at104, both motors are started in the “out” direction, and the sensors aretested, as indicated at 106, to maintain the synchronization between themotors 56 and 58. At 106 the left sensor 70 is tested to see if the leftsensor is greater than or equal to the right sensor 68, by more than theoffset plus a differential. If the left is greater, then the left motoris interrupted, as shown at 107, to allow the right motor to catch up.It should be appreciated herein that the term “interrupted” could beaccomplished by many ways; for example by reduction of power, byvariable speed motors, by clutches, and the like. As shown at 108, thesame sequencing occurs, but with respect to the right motor, and ifnecessary, an interrupt at 109 is kicked in to allow the left to catchup. This is the synchronization control process. At 110, the OUT stopposition sensor 81 b is tested to see if the room has moved to aposition equal to or beyond the OUT position. If so, the left motor 58is shut off by switch 81 b. This however allows the right motor 56 tocontinue until it is normally interrupted by the function at 109, wherethe right motor will progress to a position greater than the left sensorby more than the offset plus the differential.

[0037] It should be obvious after the above description with respect tothe movement of the room to the OUT position, that if switch 82 ispositioned to move the room in, that the appropriate sensors are alsoread at 102 a and the motors are started to move in the IN direction at104 a. A similar synchronization program is sensed at 106 a and 108 a toinsure that the left and/or right motor is not moving too quicklyrelative to the other. If it is, either the left or the right isinterrupted as mentioned before. When the room comes to a position wherethe IN position sensor is less than or equal to the IN limit position,this sensor together with switch 81 a shuts off the master motor, inthis case the left motor. The right motor is allowed to continue tooperate until the synchronization sensors interrupt the right motor at108 a where the right sensor is less than the left sensor by more thanthe offset plus the differential. It should be appreciated from theabove, in particular with reference to 106 a and 108 a, that thereference to the left sensor relative to the right sensor is “less than”as it is anticipated that the sensors would be in a digital numeralformat. Thus the digital numeric value of the closest sensor towards theend position, would have a lesser digital value than the one moredistant to the end position. If the absolute value of the difference isconsidered, than the terminology “greater than” should still becontinued.

[0038] With respect now to FIGS. 5 and 6, a second embodiment of theinvention will be shown which is similar to that of FIGS. 3 and 4, butin this case each of the right and left side have corresponding in andout stop switches, that is 81 a, 81 b, 81 c, and 81 d, and therefore itis not a master slave system. Otherwise, the system is the same as thatdepicted in FIG. 3. With reference now to FIG. 6, the operation ofreading the sensors at 202, starting the motors in the out direction at204 together with the synchronization process 206 and 208 is directlyanalogous to the above mentioned embodiment of FIG. 4 as steps 102, 104,106 and 108. The difference between the embodiment of FIG. 6 and FIG. 4is in the stop process, in that each side motor has a stop mechanism, 81a-81 d. Once again, these stop mechanisms 81 a-81 d are shown onlydiagrammatically in FIG. 5 as being located adjacent to the screws 60,62. These stop mechanisms could be mechanical limit switches, overcurrent sensors, or could simply be a switch associated directly withthe control mechanism 72. However what is incorporated into theembodiment of FIG. 5 is a mechanism to stop the motors 56, 58 wheneither the sensors 68 and 70 indicate the room is at is fully IN or OUTlimit position, or the room itself is at its full in or out positionwhich triggers some type of a stop switch.

[0039] With reference still to FIG. 6, the difference in the flowdiagram of FIG. 6 and that of FIG. 4 is in the stop mode of the rightand left motor. As shown at 210 and 212 the control mechanism 72 senseswhether the left sensor is greater than or equal to the left OUT limitposition and whether the right sensor is greater than or equal to theright OUT limit position, respectively. If either the left or rightsensor, and resultingly the room 32 is at its out limit at either theright or the left hand side, the corresponding motor is shut off at 211or 213 via the stop mechanism 81 b or 81 d. At this point, which evermotor, left or right, has been shut off, this will also trigger tocancel the synchronization at 214. This allows the corresponding rightor left motor to continue to its full OUT position, where it is shut offat either 211 or 213. As in the other designs, the moveable wall 32 issynchronized while moving in at 206 a and 208 a, and is stopped at itsleft and right IN limit positions at 210 a and 212 a in a similar manneras at the out limits described above with respect to functions 210 and212.

[0040] With respect now to FIG. 7, another control process ofcontrolling a unit as described by FIG. 5 will be discussed where theroom 32 is stopped at some arbitrary position just before its full IN orOUT limit position. For this discussion OUT reference position has beenarbitrarily set at 95% of the OUT limit position and the IN referenceposition has been arbitrarily set to be or within 5% of the IN position,but any variation of the same positions can be incorporated into theoperation. This operation will now be described with reference to FIG.7.

[0041] After started by operation of switch 82, the program thenproceeds to test at 300 to determine if the switch 82 is in the “out” or“in” position. If the switch arm 88 has been moved into contact terminal86, the room is to be moved to the extended position. As indicated at302, the sensors are read, the out limits, which are either set inmemory when the unit is manufactured or are set by the initializationsubroutine as will hereinafter be explained, are read, and an initialoffset between the sensors is read. The sensors may not have the same“zero” datum, so that the synchronization of the actuators must takeinto account the initial offset. Similarly, if the pulse type encodersare used, the initial pulse readings may be very different, so that thisinitial offset is either set when the unit is assembled or is set by theinitialization subroutine. As indicated at 304, both motors are startedin the “out” direction, and the sensors are tested, as indicated at 306,to determine if either of the sensors are reading greater than or equalto 95 percent of the “OUT” limit position. It is desirable to removesynchronization during approximately the last five percent of travel sothat each of the actuators continues to run until it achieves itsindividual stop limit.

[0042] These stop limits may be quite different between the actuators,because the actuators are commonly not positioned symmetrically withrespect to the slide out room, because their positions must accommodateobstructions, such as wheels and other underbody components. Thedeflection of the slide out room is such that, when combined with theasymmetrical positioning of the actuators, different stop limits arerequired to assure that the slide out room is properly sealed when inthe extended position. If either actuator is within five percent of its“out” limit, the termination subroutine is called as at 308. Thetermination subroutines will be described in detail hereinafter. If theactuators are not within 5% of the “out” limit, the program thenproceeds to determine, as indicated at 310, as to whether the leftsensor exceeds the right sensor by more than the offset plus arelatively small tolerance that is set initially. If the left sensordoes exceed the right sensor reading by the offset plus the tolerance,the left motor is interrupted as indicated at 312 to permit the rightmotor to “catch up” with the left.

[0043] The program then proceeds, as indicated at 314, to test as towhether the right sensor exceeds the left sensor by more than the offsetplus the tolerance. If it does, the right motor is interrupted to permitthe left actuator to “catch up”, as indicated at 316. If the test at 300indicates that the room is to be moved in towards the retractedpositions, the sensors, limits and offsets are read as indicated at 302a, both motors are started in the “in” direction as indicated in 304 aand the tests are made at 306 a, 310 a and 314 a, which correspond tothe tests made during outward movement or extension of the retractableroom at 306, 310, and 314. The right or left motors are interrupted asindicated at 312 a and 316 a, to thereby assure that the actuators arecontrolled or synchronized to permit movement of the slide out room in amanner such that the back wall of the slide room remains substantiallyparallel to the main wall of the mobile living quarters through whichthe slide out room extends, during both extension and retraction of theslide out room.

[0044] Referring now to the termination subroutine illustrateddiagrammatically in FIG. 8, when the subroutine is called by the mainprogram illustrated in FIG. 7, the switches, sensors and out/in limitsare read as indicated at 318, and the synchronization, that is,functions 310, 314, 310 a, 314 a, are canceled at 319. The switch 82 isthen tested as indicated at 320 to determine if the room is beingextended or retracted. If the room is being extended, the left sensor istested to determine if it equals or exceeds the left OUT limit positionas indicated at 322, and the right sensor is tested as indicated at 324to determine if it is equal to or greater than the right OUT limitposition. When the limits are achieved, the left and right motors areturned off as indicated at 326 and 328, it being noted that individualout limits are set for each motor, which are turned off individuallywhen their OUT limit positions are achieved. Accordingly, the slide outroom may be deflected somewhat by continued operation of one of themotors while the other motor is turned off, such limited deflectionbeing necessary in order to achieve proper sealing and to assure thatthe slide out room is fully extended over its entire length. Similarly,if the slide out room is being retracted, the left and right sensors aretested against their end limits as indicated at 322 a and 324 a, and,when the limits are attained, the right and left motors are shut off asindicated at 326 a and 328 a.

[0045] Referring now to FIG. 9, an alternate embodiment of thetermination subroutine uses mechanical limit switches to control theextended and retracted positions of the slide out room. These limitswitches are mechanical devices, well known to the skilled in the art,and are mounted to be actuated when the fully extended or fullyretracted positions of the slide out room are attained. If limitswitches are used, the limits used to control termination ofsynchronization as the slide out room approaches the extended andretracted positions are programmed into the computer and are approximatevalues. As indicated at 329 in FIG. 9, the main switch 82 is read, andthe limit switches are read. A test is made as indicated at 330 as towhether the main switch 82 is in the “in” or “out” position. If switch82 is in the out position, the left and right out limit switches aretested as indicated at 332 and 334, and the left and right motors areshut off as indicated at 336 and 338 when the limit switches aretripped. Similar tests are made of the in limit switches as indicated332 a and 334 a, and the left and right motors are accordingly shut offas indicated at 336 a and 338 a.

[0046]FIGS. 10 and 11 disclose additional embodiments of the terminationsubroutine. When the jack screws 60, 62 reach the end of their stroke ineither the in or the out direction, the current to the correspondingmotor 56 or 58 increases markedly. This indication of the end of travelcan be used to stop the motors, it being noted that, as in theembodiment of FIG. 9, that the limit at which synchronization isdiscontinued must be programmed separately as a fixed value within thecontroller or synchronization must continue until one of the motors isstopped. Referring to FIG. 10, current reference values are read asindicated at 340. These current reference values represent currentswhich are substantially higher than the normal current during freetravel. The current to the right and left motors is continually sampled,as indicated at 342 and 344, and are tested against the fixed currentreference values at 346 and 348. When the current to the correspondingmotor equals or exceeds the reference value, the motors are stopped asindicated at 350 and 352.

[0047] The termination subroutine illustrated in FIG. 11 illustrates thevariation of the termination subroutine illustrated in FIG. 10 in whichthe current is sampled to the right and left motors, as indicated at 354and 356, an average over 3.5 seconds or another appropriate time period.This average is multiplied by three or another appropriate multiple andis set equal to the right stop and left stop currents respectively.Tests are made as indicated at 358 and 360, to determine if the currentsto the left and right motors are greater than, for example, three timesthe left stop current (for the left motor) or three times the right stopcurrent (for the right motor) respectively. If these tests are met, theleft and right motors are stopped, as indicated at 362 and 364. Theadvantage of the termination routine illustrated in FIG. 11 is that thestop current is not set as a fixed amount. Since the system is normallyrun by storage batteries, which may become depleted, the current to theleft and right motors even during free travel may only be a smallfraction of the normal current. In the subroutine illustrated in FIG.11, the current is sampled during free travel, and the current at whichthe motors are stopped set at a multiple of this value, therebyobviating the problems of current never attaining the normal stopcurrent levels, or due to a low battery stopping too soon.

[0048] With respect now to FIG. 12, a further embodiment of the masterslave version is shown diagrammatically, where a clutch 57 is installedintermediate to motor 56 and gear box 64. Otherwise the embodiment isthe same as that of FIG. 4.

[0049] With respect now to FIG. 13, the process sequence beings where,once again the initialization takes place and then the system is checkedto see if whether the switch 82 is in the IN or OUT mode at 500. If theswitch is in the IN position both motors start in the IN direction at504 a. At 506 a and 508 a, the synchronization takes place to insurethat the left and/or right motor is not running ahead of the other, in asimilar manner as mentioned prior, and if it is, it is interrupted sothat the corresponding motor can catch up. At 510 a, the system checksto see if the master sensor has met its full IN limit position. If ithas not the system continues through the synchronization process, andthe motors 56 and 58 continue to operate to move the room in. When themaster sensor senses that the room is in its full IN limit position,that motor is stopped, and the system continues to run the right motoronly until it is slipping whereupon at 514 a manual termination wouldoccur, which would be by the operator.

[0050] With respect to FIG. 14, a further embodiment is shown which alsoincludes clutch mechanisms 57 and 59 positioned intermediate therespective motors and gear boxes. This version also has some type ofstop mechanism 81 a-81 d, which would stop and/or sense the location ofthe room at IN and OUT reference positions. These reference positionswould be located a short distance from the IN and OUT stop points. Forexample, the mechanisms 81 a-81 d could stop the movement of the variousmotors when it hit a certain percentage of the linear travel, forexample at 95% of its OUT stop position or within 5% of its IN stropposition. With respect now to FIG. 15, the synchronization process,would include once again at 600 determining whether the room is to bemoved IN or OUT, and thereafter reading the sensor OUT limits and offsetat 602. Both motors 56 and 58 are thereafter engaged in the OUTdirection. During the outward travel, the system will recognize whetherthe room is at its OUT reference point, as well as keep the left andright motors synchronized. More specifically, at 610 the system willtest to determine whether the sensor is equal to the OUT reference. Ifit has not, the system continues through sequences 606 and 608 where thesynchronization process occurs. If the sensor has met the OUT referenceposition, that is, the room has moved out to the reference point,somewhat short of the fully OUT stop position, and thereafter thesynchronization will be canceled at 612. This does not cancel themovement of the motors, but rather the room will continue moving outwarduntil both sides get their mechanical full OUT positions, at which pointboth clutches will begin to slip, and the operation will be manuallydiscontinued.

[0051] Up to this point, all of the previous embodiments it had sometype of electronic stopping mechanism, shown diagrammatically in theFigures as 81A or 81B, where the electronic stopping mechanism existedon at least one of the left or right sides. With respect now to FIGS.16-19, two further embodiments will be shown where there issynchronization only, but no electronic stopping mechanism on eitherside of the move out room. Rather, the synchronization will exist duringthe extension or retraction of the move out room, but mechanicalmechanisms will stop the room in the full in or fully out positions.This will be accommodated generally by mechanical stop mechanisms, forexample in the extended position where the move out room structureincludes a metal to metal engagement such as metal brackets to stop theroom, whereas in the fully retracted position, the ceiling around theroom against the wall 12 would cause the mechanism to stop. In each ofthese cases, some type of a clutch mechanism would be installed to beginslipping when a mechanical engagement takes place.

[0052] With respect first to FIG. 16, the diagrammatical view shows aclutch 59 on one side only of the drive mechanism. This would be placedon the leading side of the room as it relates to the synchronization andoff set. With respect to FIG. 17, it is shown that the control mechanism772 only includes the synchronization features of 706 and 707 with theircorresponding interrupts 707 and 709 on the out direction, and thesynchronization of 706A and 708A with their associated interrupts 707Aand 709A on the in direction. When the move out room 32 is either fullyextended or fully retracted, the move out room would engage a mechanicalstop mechanism as described above, whereupon clutch member 59 wouldbegin to slip. In this embodiment, the synchronization would continue tooperate on the opposite side of the room, and the interrupt feature ofthat synchronization process would stop the other motor. The terminationprocess for this embodiment would be to manually hear the clutchslipping, which would be an audible “ticking” noise and the operatorwould manually let off the switch 82. It should be appreciated in thisembodiment, that if the room is not properly sealed on the fullyretracted position, upon the synchronization process terminating thealternate motor as described above, the differential element subject toprocess 706 or 708 could be increased through the encoder in order toincrease the amount of override that the synchronization process wouldprovide, before executing the interrupt function 707, 707A, 709 or 709A.

[0053] With respect now to FIGS. 18 and 19, an embodiment is shown whichis very similar to that shown in FIGS. 16 and 17, but which allows bothright and left sides of the move out room to move in or out to theirtrue in or out position against a mechanical stop yet has a clutch oneach side to prevent any damage to both motor actuators. As shown inFIG. 18, each drive side has a clutch, clutch 57 on the right hand sideand clutch 59 on the left hand side. Control mechanism 872 would includesynchronization only features as shown in FIG. 19. As the move out roomis moved into its full out or full in position, the room would moveunder synchronization as described above, yet when the room is to itsfull mechanical stop position, both clutches would slip where theoperation would manually terminate. It may be the case however, that,the offset plus the differential which is programmed into thesynchronization process, would allow the synchronization process to stopthe second motor in the interrupt mode, rather than actually hitting themechanical stop.

[0054] Finally, with respect to FIGS. 20 and 21, the initializationsubroutine and the process of setting the offset will be described. FIG.20 illustrates the initialization subroutine which is called asindicated in 98 in any of FIGS. 4-19. The initialization subroutine maybe called, for example, when the set switch 94 is pushed. As discussedabove, the set switch 94 and the left and right override switches 92, 90are concealed beneath the switch cover (not shown) through which theswitch 82 projects. Accordingly, a serviceman or installer removes theswitch cover and pushes the switch 82 in either the in or outdirections, while simultaneously pushing the set switch 94. Theinitialization subroutine of FIG. 20 is then called. As indicated at 366in FIG. 20, the main switch is read, and the program is instructed toeither read the sensors or count the pulses that would be produced by anencoder. Although the rest of the subroutine is described with respectto fixed position sensors, pulse counts can be memorized as well aslimits set based on sensor readings. The switch 82 is tested, asindicated at 388, to determine if the slide out room is being eitherextended or retracted. If the room is being extended, as indicated in390, both motors are started in the “out” direction. As indicated at 392and 394, the sensors (or pulse count registers) are tested to determineif the left or right OUT limit positions have been met or exceeded. Theserviceman manually operates the room by operating the switches 92, 90until the slide out room is in the correct position for setting the setpoints.

[0055] In the case of embodiments of FIGS. 4, 6, 13, and 15 the full OUT& IN positions would be set. In the case of the embodiments of FIG. 7,reference positions are set which approximate a position just short ofwhere the OUT limit positions are to be set. When the reference OUTlimit positions have been attained for the left and right actuators, theleft and right motors are stopped accordingly, as indicated at 396 and398. The left override switch 92 is then operated while the switch 82 isin the out position, to increment the left motor while the right motorremains stopped, as indicated at 400. When the left actuator attains thedesired OUT limit position, which the serviceman determines by a numberof factors, including observing the deflection of the slide out room andcompression of any of the seals sealing the slide out room to the mainliving quarters, the override switch 92 is released and the set switch94 is pushed, as indicated at 402. The left OUT limit position is thenset equal to the sensor reading when the set switch 94 is pushed, asindicated at 404. This reading is stored in memory, and used as the outlimit until the initialization subroutine of FIG. 16 is again called.The subroutine then waits at 408, until the right stop limit has beenset in the same way. The right override switch 90 is tested and theright motor is incremented as indicated at 402 until the set switch 94is then again operated, as indicated at 412. When this occurs, the rightout limit is set equal to the sensor reading as indicated by 414. Theprogram then waits as indicated at 416, in the event that the leftsensor was not set first, whereupon the program returns.

[0056] The “in” limit positions are set in much the same way as the outlimit positions. Accordingly, both motors are started in the “in”direction as indicated at 390 a, the left and right sensors are testedas indicated at 392 a and 394 a, and the left and right motors arestopped at the reference in limits (in the case of FIG. 7) as indicatedat 396 a and 398 a, or until either “in” limit is attained, whereuponboth motors are stopped. The left override switch is tested, asindicated at 399 a, the left motor incremented as indicated at 400 a,and the in limit set by pushing the set switch 94 as indicated at 404 aand 406 a. The right override switch 90 is then operated to set the inlimit of the right actuator, as indicated by the test at 401 a, whichincrements the motor as indicated at 402 a. A test is made as to whetherthe set switch 94 is pushed, as indicated at 412 a. The right in readingis then set equal to the sensor reading, as indicated at 414 a.

[0057] The step of setting the “IN” limit position also includes thestep of setting the offset between the actuators, which is discussedabove with respect to the main routine illustrated in FIG. 4.Accordingly, as indicated at 418, the offset is set equal to thedifference between the right “IN” limit position and the left “IN” limitposition. The limits can also be set by moving the slide out room to the“in” position, setting the “in” limits and offset, and then moving theslide out room to the “out” position, preferably under synchronization,until either of the out limits are attained, whereupon both motors arestopped. The override switches 90. 92 are then used to position theslide out room where both out limits are set. Furthermore, the offsetmay be set as the difference between the “out” limits instead of the“in” limits.

[0058] Referring to FIG. 3, a variation of the way in which the offsetis set is described. The offset is set at 418 in FIG. 20 as being set asthe difference between the right “IN” limit position and the left “IN”limit position. However, it may be desirable to set the offset when theslide out room has been moved away from the “in” limits, because settingthe offsets at the “in” limits may cause the slide out room to beobstructed by other parts of the mobile living quarters. The subroutineillustrated in FIG. 21 is an alternative to the step at 418 in FIG. 20,and permits setting of the offset after the slide out room has beenadvanced away from the “in” limits. Referring to FIG. 21, the left andright override switches 92, 90 are tested as indicated at 420, 422.Accordingly, the left motor is incremented outwardly as indicated at 424if the left override switch 92 is pushed in; similarly, the right motoris incremented outwardly as indicated at 426 if the right motor overrideis pushed. Alternately, the slide out room may be incremented inwardlyfrom the out position for setting the offsets, or be incremented ineither direction from a position between the “out” and “in” limits. Theset switch 94 is then tested as indicated at 428 and 430. If theserviceman is satisfied with the location of the slide out room, the setswitch 94 is pushed (once for each of the left and right motors) and theleft sensor reading is memorized when the set switch 94 is pushed afterthe left motor override switch 92 has been operated as indicated at 432,and the sensor reading of the right sensor is memorized after the setswitch 94 is pushed after the right motor override switch 90 isoperated, as indicated at 434. After waiting until completion of theother motor. the offset, as indicated at 436 is calculated to equal thedifference between the left and right offset. Accordingly, the offset,which is used in the main program illustrated in FIG. 4, is set as thedifference in the sensor readings set by the serviceman.

[0059] It should be appreciated that many varieties of the inventioncould be conceived by those skilled in the art, utilizing the conceptsshown herein. One variety of embodiment which could be useful, would beto use the synchronization method of actuation in the vertical sense.This could be useful for such items as pop-up campers, and the like,where the expandable structure moves vertically rather thanhorizontally. In such an embodiment, the device would have more than 2,and possibly 4 actuators.

1. Mobile living quarters comprising a frame, fixed structure mounted onsaid frame defining main living quarters, expandable structure movablerelative to the fixed structure defining an auxiliary living volume saidexpandable structure being moveable between a retracted positionretracted within the main living quarters to an extended positionextended from the main living quarters, and a plurality of actuators foreffecting movement between the retracted and extended positions, each ofsaid actuators including an operating member secured to the slide outroom and extending and retracting relative to the main living quartersto effect movement of the expandable structure between the extended andretracted positions, said actuators further including position signalgenerating means for generating a position signal that varies inaccordance with the position of the operating members, and control meansfor controlling said actuators in response to said position signals,said control means including synchronizing means for controlling saidactuators to assure that the operating members extend and retract atsubstantially the same rate.
 2. Mobile living quarters as claimed inclaim 1, wherein said control means includes synchronization terminationmeans for terminating said synchronizing means before the slide out roomis moved into the fully extended position or into the fully retractedposition.
 3. Mobile living quarters as claimed in claim 1, furthercomprising means to stop the expandable structure when proximate thefully extended and fully retracted positions.
 4. Mobile living quartersas claimed in claim 3, wherein said stop means are mechanical stopswhich prevent further movement of the expandable structure.
 5. Mobileliving quarters as claimed in claim 4, further comprising at least oneclutch mechanism operatively connected to at least one clutch mechanism,which disengages said actuator upon engagement of the expandablestructure with said mechanical stops.
 6. Mobile living quarters asclaimed in claim 3, wherein said stop means are incorporated in saidcontrol means.
 7. Mobile living quarters as claimed in claim 6, whereinsaid stop means stop said actuators when in and out stop limits areattained by each actuator.
 8. Mobile living quarters as claimed in claim1, wherein said control means includes synchronization termination meansfor terminating said synchronizing means before the in and out stoplimit positions are attained by either actuator to permit each actuatorto move to its in and out stop limit positions independently of theother actuator.
 9. Mobile living quarters as claimed in claim 8, whereinsaid synchronization termination means includes a comparing means forcomparing each of said position signals with an out reference level whenthe slide out room is moved toward the extended position and forcomparing each of said position signals with an in reference level whenthe slide out room is moved toward the retracted position, saidsynchronization termination means being responsive to said comparingmeans for terminating said synchronizing means when either of saidposition signals attains either of said reference levels.
 10. Mobileliving quarters as claimed in claim 9, wherein said reference levels areset as a predetermined fraction of the in and out stop limits. 11.Mobile living quarters as claimed in claim 3, wherein in and out limitswitches are mounted for actuation by each of said actuators, said inand out limit switches establishing said in and out stop limits. 12.Mobile living quarters as claimed in claim 1, wherein said control meansincludes setting means for setting said in and out stop limits, saidsetting means including measuring means for measuring the electriccurrent drawn by each of said actuators, and current comparing means forcomparing said electrical current drawn by each of said actuators with apredetermined reference level and setting said in and out stop limit foreach actuator when the current drawn by the corresponding actuatorexceeds the predetermined reference level.
 13. Mobile living quarters asclaimed in claim 1, wherein said control means includes setting meansfor setting said in and out stop limits, said setting means includingmeasuring means for measuring the electric current drawn by each of saidactuators, means for averaging the current drawn from each of saidactuators over a predetermined time period to establish an averagecurrent draw, means for comparing the average current draw with amultiple of the average current draw and setting the corresponding stoplimit when the average current draw exceeds said multiple of the averagecurrent draw.
 14. Mobile living quarters as claimed in claim 1, whereinsaid synchronizing means includes reading means for reading sensoroutput signals generated by each of said sensors, calculating means forforming the difference between said output signals, and interrupting oneof said actuators when the difference between output signal of said oneactuator exceeds the output signal of the other sensor by more than apredetermined offset.
 15. Mobile living quarters as claimed in claim 14,wherein said calculating means includes means for setting said offset asthe difference between said output signals when the slide out room is inthe fully retracted position.
 16. Mobile living quarters as claimed inclaim 14, wherein said calculating means includes means for setting saidoffset as the difference between said output signals when the slide outroom is in a position other than the fully retracted position. 17.Mobile living quarters as claimed in claim 14, wherein said expandablestructure is defined as a slide out room moveable horizontally relativeto said fixed structure.
 18. Mobile living quarters as defined in claim1, comprising more than 1 pair of actuators.
 19. Mobile living quartersas defined in claim 1, wherein said expandable structure is movablevertically relative to said fixed structure.
 20. Mobile living quartersas defined by claim 1, further comprising a stop mechanism for stoppingsaid expandable structure at a predetermined position.
 21. Mobile livingquarters as defined by claim 20, wherein the predetermined positionincludes fully extended and fully retracted position.
 22. Mobile livingquarters as defined by claim 20, wherein the predetermined positionincludes a percentage of the fully extended and fully retractedposition.
 23. Mobile living quarters as defined by claim 22, wherein thepredetermined position is approximately 5% before the fully retractedposition and 95% the fully extended position.
 24. Mobile living quartersas defined by claim 20, wherein the stop mechanism is located on onlyone actuator.
 25. Mobile living quarters as defined by claim 20, whereinthe stop mechanism is located on both actuators.
 26. Mobile livingquarters as defined by claim 16, where a clutch is positionedoperatively connected to said actuator.
 27. Mobile living quarters asdefined by claim 25, further comprising clutches positioned operativelyconnected to each actuator.
 28. Mobile living quarters as defined byclaim 23, further comprising means to terminate the synchronizationmeans, at said predetermined position.
 29. Mobile living quarterscomprising a frame, fixed structure mounted on said frame defining mainliving quarters, expandable structure movable relative to the fixedstructure defining an auxiliary living volume, mounting means formounting said expandable structure for sliding movement relative to themain living quarters for movement between a retracted position retractedwithin the main living quarters to an extended position extended fromthe main living quarters, and a plurality of actuators for effectingmovement between the retracted and extended positions, each of saidactuators including an operating member secured to the slide out roomand extending and retracting relative to the main living quarters toeffect movement of the slide out room between the extended and retractedpositions, said actuators further including position signal generatingmeans for generating a position signal that varies in accordance withthe position of the operating members, and control means for controllingsaid actuators in response to said position signals, said control meansincluding setting means for setting in and out stop limits for saidactuators.
 30. Mobile living quarters as claimed in claim 29, whereinsaid setting means includes measuring means for measuring the electriccurrent drawn by each of said actuators, means for averaging the currentdrawn from each of said actuators over a predetermined time period toestablish an average current draw, and means for setting said in and outstop limits as a function of said average current draw.
 31. Mobileliving quarters as claimed in claim 29, wherein said control meansincludes comparing means for comparing the average current draw with amultiple of the average current draw and setting the corresponding stoplimit when the average current draw exceeds said multiple of the averagecurrent draw.
 32. Mobile living quarters as claimed in claim 29, whereincurrent comparing means compares said electrical current drawn by eachof said actuators with a predetermined reference level and setting saidin and out stop limit for each actuator when the current drawn by thecorresponding actuator exceeds the predetermined reference level. 33.Mobile living quarters comprising a frame, fixed structure mounted onsaid frame defining main living quarters, expandable structure movablerelative to the fixed structure defining an auxiliary living volume,mounting means for mounting said expandable structure for movementbetween a retracted position retracted within the main living quartersto an extended position extended from the main living quarters, and apair of independent actuators for effecting movement between theretracted and extended positions, each of said actuators including anoperating member secured to the slide out room and extending andretracting relative to the main living quarters to effect movement ofthe expandable structure between the extended and retracted positions,said actuators further including position signal generating means forgenerating a position signal that varies in accordance with the positionof the operating members, and control means for controlling saidactuators in response to said position signals, said control meansincluding setting means for setting in and out stop limits for saidactuators, said setting means including a first switch for controllingone of said actuators independently of the one actuator and a secondswitch for controlling the other actuator independently of the oneactuator to permit each of said actuators to be moved independently to adesired stop limit, and set means for causing said control means tomemorize the position signals generated by the position sensors at saiddesired stop limits.
 34. Mobile living quarters as claimed in claim 33,wherein said stop limits include room in stop limits and room out stoplimits.
 35. Mobile living quarters as claimed in claim 33, wherein saidcontrol means includes synchronizing means for controlling saidactuators to assure that the operating members extend and retract atsubstantially the same rate including calculating means for readingsensor output signals generated by each of said sensors, calculatingmeans for forming the difference between said output signals, andinterrupting means for interrupting one of said actuators when thedifference between output signal of said one actuator exceeds the outputsignal of the other sensor by more than a predetermined offset. 36.Mobile living quarters as claimed in claim 35, wherein said stop limitsinclude room in stop limits and room out stop limits, and calibratingmeans for setting said offset equal to the difference between the sensoroutput signals at the room in stop limits.
 37. Mobile living quarters asclaimed in claim 35, wherein said stop limits include room in stoplimits and room out stop limits, and calibrating means for setting saidoffset equal to the difference between the sensor output signals at thedifference between the sensor output signals when the expandablestructure is in a calibrating position, said calibrating position beinga position other than the fully retracted position.
 38. Mobile livingquarters as claimed in claim 37, wherein said slide out room is moved tothe calibrating position by independently operating said first andsecond switches to move the expandable structure to a selectedcalibrating position, said calculating means including memory meansresponsive to said set switch for forming the difference between saidposition signals and memorizing said difference as said offset. 39.Method of calibrating an actuation mechanism for a slide out roomdefining an auxiliary living space of mobile living quarters, saidactuation mechanism including a plurality of actuators for effectingmovement of the slide out room from a fully extended position to a fullyretracted position in which the slide out room is retracted into themobile living quarters, each of said actuators including position signalgenerating means for generating a position signal that varies inaccordance with the position of the corresponding actuator, comprisingthe steps of operating both of said actuators to advance said slide outroom toward said and retracted position, stopping said slide out roomwhen the slide out room is in the fully retracted position, reading thesignals generated by said position sensors when the slide out room is inthe retracted position, and setting the value of the position signalread as the corresponding IN limit.
 40. Method as set forth in claim 39,wherein the steps are repeated to set the corresponding limits for theother position.
 41. Method as set forth in claim 39, wherein said methodincludes the step of synchronizing said actuators for movement towardsaid one position at substantially the same rate.
 42. Method as setforth in claim 39, wherein said method includes the steps ofsynchronizing said actuators as the slide out room is moved from oneposition to the other position by interrupting one of said actuators ifthe position signal representing the position of said one actuatorexceeds the position signal representing the position of the otheractuator by more than a predetermined offset.
 43. Method as set forth inclaim 42, including the steps of setting said offset as the differencebetween the position signals when the slide out room is in the fullyretracted position.
 44. Method as set forth in claim 42, including thesteps of moving the slide out room away from the fully retractedposition, operating said first and second switches to independentlyoperate said actuators to bring the slide out room into a condition inwhich the slide out room has a desired orientation with respect to themain living quarters, and setting said offset as equal to the differencebetween said position signals when the slide out room is in saidcondition.
 45. Mobile living quarters comprising a frame, structuremounted on said frame defining main living quarters, an expandablestructure movable relative to the fixed structure defining auxiliaryliving quarters, mounting means for mounting said expandable structurefor sliding movement relative to the fixed structure for movementbetween a retracted position retracted within said fixed structure, toan extended position extended from the fixed structure, and a pair ofindependent actuators for effecting movement between the retracted andextended positions, each of said actuators including an operating membersecured to the expandable structure and extending and retractingrelative to the main living quarters to effect movement of theexpandable structure between the extended and retracted positions, afirst signal generator for generating a first position signal thatvaries in accordance with the position of the operating member of one ofsaid actuators and a second signal generator for generating a secondposition signal that varies in accordance with the position of theoperating member of the other actuator, and a controller responsive tosaid position signals for turning off a corresponding actuator when thecorresponding position signal indicates the slide out room has attaineda predetermined stopping position.
 46. Mobile living quarters as claimedin claim 45, wherein the controller turns off the actuator when thecorresponding position signal indicates the slide out room has attainedthe fully retracted position.
 47. Mobile living quarters as claimed inclaim 45, wherein the controller turns off the actuator when thecorresponding position signal indicates the slide out room has attainedthe fully extended position.
 48. Mobile living quarters as claimed inclaim 45, wherein said controller includes means for comparing saidfirst position signal with a first room-out reference representing thevalue of the first position signal when the slide out room is in theextended position and comparing said second position signal with asecond room-out reference representing the value of the second positionsignal when the slide out room is in the extended position, andterminating means for terminating operation of the first actuator whenthe first position signal attains the first room-out reference and forterminating the second actuator when the second position signal attainsthe second room-out reference.
 49. Mobile living quarters as claimed inclaim 45, wherein each of said actuators includes an electric motoroperating a corresponding operating member.
 50. Mobile living quartersas claimed in claim 45, wherein said controller includes means forcomparing said first position signal with a first room-in referencerepresenting the value of the first position signal when the slide outroom in the retracted position and comparing said second position signalwith a second room-in reference representing the value of the secondposition signal when the slide out room is in the retracted position,and terminating means for terminating operation of the first actuatorwhen the first position signal attains the first room in reference andfor terminating the second actuator when the second position signalattains the second room-in reference.
 51. Mobile living quarterscomprising a frame, fixed structure mounted on said frame defining mainliving quarters, expandable structure movable relative to the fixedstructure defining an auxiliary living volume, mounting means formounting said expandable structure for movement between a retractedposition retracted within the main living quarters to an extendedposition extended from the main living quarters, and a pair ofindependent actuators for effecting movement between the retracted andextended positions, each of said actuators including an operating membersecured to the slide out room and extending and retracting relative tothe main living quarters to effect movement of the expandable structurebetween the extended and retracted positions, said actuators furtherincluding position signal generating means for generating a positionsignal that varies in accordance with the position of the operatingmembers, and control means for controlling said actuators in response tosaid position signals, said control means including synchronizing meansfor controlling said actuators to assure that the operating membersextend and retract at substantially the same rate by maintaining apredetermined offset between said position signals, and means forsetting said offset equal to the difference in said position signalswhen the operating members are advanced to a predetermined position. 52.Mobile living quarters as claimed in claim 51, wherein said controlmeans includes setting means for setting said offset, said setting meansincluding a first switch for controlling one of said actuatorsindependently of the one actuator and a second switch for controllingthe other actuator independently of the one actuator to permit each ofsaid actuators to be moved independently to a desired position, and setmeans for causing said control means to memorize the difference betweensaid position signals at said desired position as said offset. 53.Method of calibrating an actuation mechanism for a slide out roomdefining an auxiliary living space of mobile living quarters, saidactuation mechanism including a pair of independent actuators foreffecting movement of the slide out room from a fully extended positionto a fully retracted position in which the slide out room is retractedinto the mobile living quarters, each of said actuators includingposition signal generating means for generating a position signal thatvaries in accordance with the position of the corresponding actuator,comprising the steps of setting a predetermined offset between saidposition signals, and then synchronizing said actuators as the slide outroom is moved from said one position to the other position byinterrupting one of said actuators if the position signal representingthe position of said one actuator exceeds the position signalrepresenting the position of the other actuator by more than saidpredetermined offset.
 54. Method as set forth in claim 53, including thesteps of setting said offset as the difference between the positionsignals when the slide out room is in the fully retracted position. 55.Method as set forth in claim 53, including the steps of moving the slideout room away from the fully retracted position, operating first andsecond switches to independently operate said actuators to bring theslide out room into a condition in which the slide out room. has adesired orientation with respect to the main living quarters, andsetting said offset as equal to the difference between said positionsignals when the slide out room is in said condition.
 56. Mobile livingquarters comprising a frame, structure mounted on said frame definingmain living quarters, a slide out room defining auxiliary livingquarters, mounting means for mounting said slide out room for slidingmovement relative to the main living quarters for movement between aretracted position retracted within the main living quarters to anextended position extended from the main living quarters, and a pair ofindependent actuators for effecting movement between the retracted andextended positions, each of said actuators including an operating membersecured to the slide out room and extending and retracting relative tothe main living quarters to effect movement of the slide out roombetween the extended and retracted positions, measuring means formeasuring the electric current drawn by each of said actuators, andmeans for stopping at least the one actuator when the current drawexceeds a predetermined limit which is a function of the current draw.57. The mobile living quarters set forth in claim 56, wherein themeasuring means includes means for averaging the current drawn from atleast one of said actuators over a predetermined time period toestablish an average current draw, means for comparing the averagecurrent draw with a multiple of the average current draw.
 58. The mobileliving quarters set forth in claim 56, wherein the measuring meansincludes means for measuring the peak current over a given time, andsaid predetermined limit is a multiple of the peak current.
 59. Themobile living quarters set forth in claim 56, wherein said actuatorsinclude position signal generating means for generating a positionsignal that varies in accordance with the position of the operatingmembers, and control means for controlling said actuators in response tosaid position signals.
 60. A method of controlling the movement of aslide out room of mobile living quarters, comprising the steps of movingthe slide out room to a fully retracted position, setting this positionas a reference position, and operating the room between extendedretracted positions, in a position parallel to said reference position.